Comparing Triflate and Hexafluorophosphate Anions of Ionic Liquids in Polymer Electrolytes for Supercapacitor Applications

Two different ionic liquid-based biopolymer electrolyte systems were prepared using a solution casting technique. Corn starch and lithium hexafluorophosphate (LiPF₆) were employed as polymer and salt, respectively. Additionally, two different counteranions of ionic liquids, viz. 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF₆) and 1-butyl-3-methylimidazolium trifluoromethanesulfonate (also known as 1-butyl-3-methylimidazolium triflate) (BmImTf) were used and studied in this present work. The maximum ionic conductivities of (1.47 ± 0.02) × 10⁻⁴ and (3.21 ± 0.01) × 10⁻⁴ S·cm⁻¹ were achieved with adulteration of 50 wt% of BmImPF₆ and 80 wt% of BmImTf, respectively at ambient temperature. Activated carbon-based electrodes were prepared and used in supercapacitor fabrication. Supercapacitors were then assembled using the most conducting polymer electrolyte from each system. The electrochemical properties of the supercapacitors were then analyzed. The supercapacitor containing the triflate-based biopolymer electrolyte depicted a higher specific capacitance with a wider electrochemical stability window compared to that of the hexafluorophosphate system.     

Effects of non-steroidal anti-inflammatory drugs and prostaglandins on alkali secretion by rabbit gastric fundus in vitro

The effects of non-steroidal anti-inflammatory drugs and prostaglandins E₂ and F_2α on the secretory and electrical activity of isolated rabbit fundic mucosa have been studied. Spontaneous acid secretion was inhibited by serosal side application of sodium thiocyanate (6×10⁻²M) and the resulting alkali secretion measured by pH stat tiration. Serosal side application of indomethacin (10⁻⁵M) or aspirin (3×10⁻³M) inhibited alkali secretion (0·55±0·06 to 0·12±0·06 μmol/cm²/h, n=6, p<0·01 and 0·28±0·06 to 0·11±0·03 μmol/cm²/h, n=7, p<0·02 respectively). Mucosal or serosal side prostaglandin E₂ (10⁻⁵ to 10⁻¹⁰M) and F_2α (10⁻⁴ to 10⁻¹⁰M) failed to alter the rate of alkalinisation but secretion was significantly increased by serosal side 16,16-dimethyl-prostaglandin E₂ (10⁻⁶M) (0·90±0·20 to 1·50±0·30 μmol/cm²/h, n=6, p<0·01). Serosal side application of 10⁻⁶M prostaglandin E₂ to fundic mucosae pretreated with either aspirin (5×10⁻³M) or indomethacin (10⁻⁵M), to reduce endogenous E₂ formation, also failed to alter alkali secretion. Pretreatment of the mucosa with 16,16-dimethyl-E₂ (10⁻⁶M) abolished the inhibitory effect of indomethacin (10⁻⁵M) on alkali secretion (n=6) but did not modify the secretory response to aspirin (3×10⁻³M) (fall in alkali secretion with aspirin = 81±11% and with aspirin plus 16,16-dimethyl-E₂ = 72±10%, n=7). In the doses used, none of the prostaglandins or non-steroidal anti-inflammatory drugs altered transmucosal potential difference or electrical resistance. These results show that the damaging agents, aspirin and indomethacin, both inhibit gastric alkali secretion but that modes of action may differ. The observation that prostaglandins, E₂ and F_2α failed to increase alkali production suggests that their protective activity against a variety of damaging agents as shown by others, may be mediated by another mechanism.     

Fickian-Based Empirical Approach for Diffusivity Determination in Hollow Alginate-Based Microfibers Using 2D Fluorescence Microscopy and Comparison with Theoretical Predictions

Hollow alginate microfibers (od = 1.3 mm, id = 0.9 mm, th = 400 µm, L = 3.5 cm) comprised of 2% (w/v) medium molecular weight alginate cross-linked with 0.9 M CaCl₂ were fabricated to model outward diffusion capture by 2D fluorescent microscopy. A two-fold comparison of diffusivity determination based on real-time diffusion of Fluorescein isothiocyanate molecular weight (FITC MW) markers was conducted using a proposed Fickian-based approach in conjunction with a previously established numerical model developed based on spectrophotometric data. Computed empirical/numerical (D_empiricial/D_numerical) diffusivities characterized by small standard deviations for the 4-, 70- and 500-kDa markers expressed in m²/s are (1.06 × 10⁻⁹ ± 1.96 × 10⁻¹⁰)/(2.03 × 10⁻¹¹), (5.89 × 10⁻¹¹ ± 2.83 × 10⁻¹²)/(4.6 × 10⁻¹²) and (4.89 × 10⁻¹² ± 3.94 × 10⁻¹³)/(1.27 × 10⁻¹²), respectively, with the discrimination between the computation techniques narrowing down as a function of MW. The use of the numerical approach is recommended for fluorescence-based measurements as the standard computational method for effective diffusivity determination until capture rates (minimum 12 fps for the 4-kDa marker) and the use of linear instead of polynomial interpolating functions to model temporal intensity gradients have been proven to minimize the extent of systematic errors associated with the proposed empirical method.     

INAUGURAL ARTICLE by a Recently Elected Academy Member:In vitro evolution of horse heart myoglobin to increase peroxidase activity

Random mutagenesis and screening for enzymatic activity has been used to engineer horse heart myoglobin to enhance its intrinsic peroxidase activity. A chemically synthesized gene encoding horse heart myoglobin was subjected to successive cycles of PCR random mutagenesis. The mutated myoglobin gene was expressed in Escherichia coli LE392, and the variants were screened for peroxidase activity with a plate assay. Four cycles of mutagenesis and screening produced a series of single, double, triple, and quadruple variants with enhanced peroxidase activity. Steady-state kinetics analysis demonstrated that the quadruple variant T39I/K45D/F46L/I107F exhibits peroxidase activity significantly greater than that of the wild-type protein with k₁ (for H₂O₂ oxidation of metmyoglobin) of 1.34 × 10⁴ M⁻¹ s⁻¹ (≈25-fold that of wild-type myoglobin) and k₃ [for reducing the substrate (2, 2′-azino-di-(3-ethyl)benzthiazoline-6-sulfonic acid] of 1.4 × 10⁶ M⁻¹ s⁻¹ (1.6-fold that of wild-type myoglobin). Thermal stability of these variants as measured with circular dichroism spectroscopy demonstrated that the T_m of the quadruple variant is decreased only slightly compared with wild-type (74.1°C vs. 76.5°C). The rate constants for binding of dioxygen exhibited by the quadruple variant are identical to the those observed for wild-type myoglobin (k_on, 22.2 × 10⁻⁶ M⁻¹ s⁻¹ vs. 22.3 × 10⁻⁶ M⁻¹ s⁻¹; k_off, 24.3 s⁻¹ vs. 24.2 s⁻¹; K_O2, 0.91 × 10⁻⁶ M⁻¹ vs. 0.92 × 10⁻⁶ M⁻¹). The affinity of the quadruple variant for CO is increased slightly (k_on, 0.90 × 10⁻⁶ M⁻¹s⁻¹ vs. 0.51 × 10⁻⁶ M⁻¹s⁻¹; k_off, 5.08 s⁻¹ vs. 3.51 s⁻¹; K_CO, 1.77 × 10⁻⁷ M⁻¹ vs. 1.45 × 10⁻⁷ M⁻¹). All four substitutions are in the heme pocket and within 5 Å of the heme group.     

Enhanced Storage Performance of PANI and PANI/Graphene Composites Synthesized in Protic Ionic Liquids

Polyaniline (PANI) was synthesized using oxidative polymerization in a mixture of water with pyrrolidinium hydrogen sulfate [Pyrr][HSO₄], which is a protic ionic liquid PIL. The obtained PANI (PANI/PIL) was compared with conventional PANI (PANI/HCl and PANI/HSO₄) in terms of their morphological, structural, and storage properties. The results demonstrate that the addition of this PIL to a polymerization medium leads to a fiber-like morphology, instead of a spherical-like morphology, of PANI/HSO₄ or an agglomerated morphology of PANI/HCl. In addition, PAN/PIL exhibits an improvement of the charge transfer kinetic and storage capability in H₂SO₄ 1 mol·L⁻¹, compared to PANI/HCl. The combination of PANI/PIL and graphene oxide (GO), on the other hand, was investigated by optimizing the PANI/GO weight ratio to achieve the nanocomposite material with the best performance. Our results indicate that the PANI/PIL/GO containing 16 wt% of GO material exhibits a high performance and stability (223 F·g⁻¹ at 10 A·g⁻¹ in H₂SO₄ 1 mol·L⁻¹, 4.9 Wh·Kg⁻¹, and 3700 W·Kg⁻¹ @ 10 A·g⁻¹). The obtained results highlight the beneficial role of PIL in building PANI and PANI/GO nanocomposites with excellent performances for supercapacitor applications.     

Construction of a Three-Dimensional BaTiO3 Network for Enhanced Permittivity and Energy Storage of PVDF Composites

Three-dimensional BaTiO₃ (3D BT)/polyvinylidene fluoride (PVDF) composite dielectrics were fabricated by inversely introducing PVDF solution into a continuous 3D BT network, which was simply constructed via the sol-gel method using a cleanroom wiper as a template. The effect of the 3D BT microstructure and content on the dielectric and energy storage properties of the composites were explored. The results showed that 3D BT with a well-connected continuous network and moderate grain sizes could be easily obtained by calcining a barium source containing a wiper template at 1100 °C for 3 h. The as-fabricated 3D BT/PVDF composites with 21.1 wt% content of 3D BT (3DBT–2) exhibited the best comprehensive dielectric and energy storage performances. An enhanced dielectric constant of 25.3 at 100 Hz, which was 2.8 times higher than that of pure PVDF and 1.4 times superior to the conventional nano–BT/PVDF 25 wt% system, was achieved in addition with a low dielectric loss of 0.057 and a moderate dielectric breakdown strength of 73.8 kV·mm⁻¹. In addition, the composite of 3DBT–2 exhibited the highest discharge energy density of 1.6 × 10⁻³ J·cm⁻³ under 3 kV·mm⁻¹, which was nearly 4.5 times higher than that of neat PVDF.     

Microstructure and Wear Properties of Laser Cladding WC/Ni-Based Composite Layer on Al–Si Alloy

The microstructural and wear properties of laser-cladding WC/Ni-based layer on Al–Si alloy were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and wear-testing. The results show that, compared with the original specimen, the microhardness and wear resistance of the cladding layer on an Al–Si alloy were remarkably improved, wherein the microhardness of the layer achieved 1100 HV and the average friction coefficient of the layer was barely 0.14. The mainly contributor to such significant improvement was the generation of a WC/Ni-composite layer of Al–Si alloy during laser cladding. Two types of carbides, identified as M₇C₃ and M₂₃C₆, were found in the layer. The wear rate of the layer first increased and then decreased with the increase in load; when the load was 20 N, 60 N and 80 N, the wear rate of layer was1.89 × 10⁻³ mm³·m⁻¹, 3.73 × 10⁻³ mm³·m⁻¹ and 2.63 × 10⁻³ mm³·m⁻¹, respectively, and the average friction coefficient (0.14) was the smallest when the load was 60 N.     

Rapid Detection of Listeria by Bacteriophage Amplification and SERS-Lateral Flow Immunochromatography

A rapid Listeria detection method was developed utilizing A511 bacteriophage amplification combined with surface-enhanced Raman spectroscopy (SERS) and lateral flow immunochromatography (LFI). Anti-A511 antibodies were covalently linked to SERS nanoparticles and printed onto nitrocellulose membranes. Antibody-conjugated SERS nanoparticles were used as quantifiable reporters. In the presence of A511, phage-SERS nanoparticle complexes were arrested and concentrated as a visible test line, which was interrogated quantitatively by Raman spectroscopy. An increase in SERS intensity correlated to an increase in captured phage-reporter complexes. SERS limit of detection was 6 × 10⁶ pfu·mL⁻¹, offering detection below that obtainable by the naked eye (LOD 6 × 10⁷ pfu·mL⁻¹). Phage amplification experiments were carried out at a multiplicity of infection (MOI) of 0.1 with 4 different starting phage concentrations monitored over time using SERS-LFI and validated by spot titer assay. Detection of L. monocytogenes concentrations of 1 × 10⁷ colony forming units (cfu)·mL⁻¹, 5 × 10⁶ cfu·mL⁻¹, 5 × 10⁵ cfu·mL⁻¹ and 5 × 10⁴ cfu·mL⁻¹ was achieved in 2, 2, 6, and 8 h, respectively. Similar experiments were conducted at a constant starting phage concentration (5 × 10⁵ pfu·mL⁻¹) with MOIs of 1, 2.5, and 5 and were detected in 2, 4, and 5 h, respectively.     

Electrochemically Activated Screen-Printed Carbon Sensor Modified with Anionic Surfactant (aSPCE/SDS) for Simultaneous Determination of Paracetamol,Diclofenac and Tramadol

In this work, an electrochemically activated screen-printed carbon electrode modified with sodium dodecyl sulfate (aSPCE/SDS) was proposed for the simultaneous determination of paracetamol (PA), diclofenac (DF), and tramadol (TR). Changes of surface morphology and electrochemical behaviour of the electrode after the electrochemical activation with H₂O₂ and SDS surface modification were studied by scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The influence of various parameters on the responses of the aSPCE/SDS such as pH and concentration of the buffer, SDS concentration, and techniques parameters were investigated. Using optimised conditions (E_acc. of −0.4 V, t_acc. of 120 s, ΔE_A of 150 mV, ν of 250 mV s⁻¹, and t_m of 10 ms), the aSPCE/SDS showed a good linear response in the concentration ranges of 5.0 × 10⁻⁸–2.0 × 10⁻⁵ for PA, 1.0 × 10⁻⁹–2.0 × 10⁻⁷ for DF, and 1.0 × 10⁻⁸–2.0 × 10⁻⁷ and 2.0 × 10⁻⁷–2.0 × 10⁻⁶ mol L⁻¹ for TR. The limits of detection obtained during the simultaneous determination of PA, DF, and TR are 1.49 × 10⁻⁸ mol L⁻¹, 2.10 × 10⁻¹⁰ mol L⁻¹, and 1.71 × 10⁻⁹ mol L⁻¹, respectively. The selectivity of the aSPCE/SDS was evaluated by examination of the impact of some inorganic and organic substances that are commonly present in environmental and biological samples on the responses of PA, DF, and TR. Finally, the differential pulse adsorptive stripping voltammetric (DPAdSV) procedure using the aSPCE/SDS was successfully applied for the determination of PA, DF, and TR in river water and serum samples as well as pharmaceuticals.     

Intravoxel Incoherent Motion MR Imaging: Comparison of Diffusion and Perfusion Characteristics for Differential Diagnosis of Soft Tissue Tumors

We used intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) to explore the possibility of preoperative diagnosis of soft tissue tumors (STTs). This prospective study enrolled 23 patients. Conventional MRI and IVIM examinations were performed on a 3.0T MR imager. Eight (35%) hemangiomas, 11 (47%) benign soft tissue tumors excluding hemangiomas (BSTTEHs) and 4 soft tissue sarcomas (STSs) were assessed. The mean tumor size was about 1652.36 ± 233.66 mm². Ten b values (0–800 s/mm²) were used to evaluate diffusion and perfusion characteristics of IVIM. IVIM parameters (ADC_standard, ADC_slow, ADC_fast, and f) of STTs were measured and evaluated for differentiating hemangiomas, BSTTEHs, and STSs. ADC_slow and ADC_fast value were different for hemangiomas, BSTTEHs, and STSs separately (P < 0.001, P < 0.001, and P = 0.001). ADC_slow, cut-off value smaller than 0.93 × 10^–3 mm²/s, was the best parameter to differ STSs (0.689 ± 0.173 × 10⁻³ mm²/s) from hemangiomas (0.933 ± 0.237 × 10⁻³ mm²/s) and BSTTEHs (1.156 ± 0.120 × 10⁻³ mm²/s) (P = 0.001). ADC_slow (0.93 × 10⁻³ mm²/s <cut-off value <0.96 × 10⁻³ mm²/s) was used to distinguish hemangiomas from BSTTs. There were significant difference among hemangiomas, BSTTEHs, and STSs (P = 0.014, P = 0.036, P < 0.001). The ADC_standard, ADC_fast, and f value were different (P < 0.05) for STSs (1.009 ± 0.177 × 10⁻³ mm²/s, 15.700 ± 1.992 × 10⁻³ mm²/s, 0.503 ± 0.068), hemangiomas (1.505 ± 0.226 × 10⁻³ mm²/s, 11.675 ± 0.456 × 10⁻³ mm²/s, 0.682 ± 0.060), and BSTTEHs (1.555 ± 0.176 × 10⁻³ mm²/s, 11.727 ± 0.686 × 10⁻³ mm²/s, 0.675 ± 0.054). And there was no significant difference for these 3 parameters between hemangiomas and BSTTEHs (P = 0.584, 0.907, and 0.798). IVIM may be of significant value for differential diagnosing hemangiomas, BSTTEHs, and STSs.     

Phytosulfokine-α, a sulfated pentapeptide, stimulates the proliferation of rice cells by means of specific high- and low-affinity binding sites

Peptide growth factors were isolated from conditioned medium derived from rice (Oryza sativa L.) suspension cultures and identified to be a sulfated pentapeptide [H-Tyr(SO₃H)-Ile-Tyr(SO₃H)-Thr-Gln-OH] and its C-terminal-truncated tetrapeptide [H-Tyr(SO₃H)-Ile-Tyr(SO₃H)-Thr-OH]. These structures were identical to the phytosulfokines originally found in asparagus (Asparagus officinalis L.) mesophyll cultures. The pentapeptide [phytosulfokine-α (PSK-α)] very strongly stimulated colony formation of rice protoplasts at concentrations above 10⁻⁸ M, indicating a similar mode of action in rice of phytosulfokines. Binding assays using ³⁵S-labeled PSK-α demonstrated the existence of both high- and low-affinity specific saturable binding sites on the surface of rice cells in suspension. Analysis of [³⁵S]PSK-α binding in differential centrifugation fractions suggested association of the binding with a plasma membrane-enriched fraction. The apparent K_d values for [³⁵S]PSK-α binding were found to be 1 × 10⁻⁹ M for the high-affinity type and 1 × 10⁻⁷ M for the low-affinity type, with maximal numbers of binding sites of 1 × 10⁴ sites per cell and 1 × 10⁵ sites per cell, respectively. Competition studies with [³⁵S]PSK-α and several synthetic PSK-α analogs demonstrated that only peptides that possesses mitogenic activity can effectively displace the radioligand. These results suggest that a signal transduction pathway mediated by peptide factors is involved in plant cell proliferation.     

Hysteresis in Lanthanide Zirconium Oxides Observed Using a Pulse CV Technique and including the Effect of High Temperature Annealing

A powerful characterization technique, pulse capacitance-voltage (CV) technique, was used to investigate oxide traps before and after annealing for lanthanide zirconium oxide thin films deposited on n-type Si (111) substrates at 300 °C by liquid injection Atomic Layer Deposition (ALD). The results indicated that: (1) more traps were observed compared to the conventional capacitance-voltage characterization method in LaZrO_x; (2) the time-dependent trapping/de-trapping was influenced by the edge time, width and peak-to-peak voltage of a gate voltage pulse. Post deposition annealing was performed at 700 °C, 800 °C and 900 °C in N₂ ambient for 15 s to the samples with 200 ALD cycles. The effect of the high temperature annealing on oxide traps and leakage current were subsequently explored. It showed that more traps were generated after annealing with the trap density increasing from 1.41 × 10¹² cm⁻² for as-deposited sample to 4.55 × 10¹² cm⁻² for the 800 °C annealed one. In addition, the leakage current density increase from about 10⁻⁶ A/cm² at V_g = +0.5 V for the as-deposited sample to 10⁻³ A/cm² at V_g = +0.5 V for the 900 °C annealed one.     

Kinetics of the Organic Compounds and Ammonium Nitrogen Electrochemical Oxidation in Landfill Leachates at Boron-Doped Diamond Anodes

Electrochemical oxidation (EO) of organic compounds and ammonium in the complex matrix of landfill leachates (LLs) was investigated using three different boron-doped diamond electrodes produced on silicon substrate (BDD/Si)(levels of boron doping [B]/[C] = 500, 10,000, and 15,000 ppm—0.5 k; 10 k, and 15 k, respectively) during 8-h tests. The LLs were collected from an old landfill in the Pomerania region (Northern Poland) and were characterized by a high concentration of N-NH₄⁺ (2069 ± 103 mg·L⁻¹), chemical oxygen demand (COD) (3608 ± 123 mg·L⁻¹), high salinity (2690 ± 70 mg Cl⁻·L⁻¹, 1353 ± 70 mg SO₄²⁻·L⁻¹), and poor biodegradability. The experiments revealed that electrochemical oxidation of LLs using BDD 0.5 k and current density (j) = 100 mA·cm⁻² was the most effective amongst those tested (C_8h/C₀: COD = 0.09 ± 0.14 mg·L⁻¹, N-NH₄⁺ = 0.39 ± 0.05 mg·L⁻¹). COD removal fits the model of pseudo-first-order reactions and N-NH₄⁺ removal in most cases follows second-order kinetics. The double increase in biodegradability index—to 0.22 ± 0.05 (BDD 0.5 k, j = 50 mA·cm⁻²) shows the potential application of EO prior biological treatment. Despite EO still being an energy consuming process, optimum conditions (COD removal > 70%) might be achieved after 4 h of treatment with an energy consumption of 200 kW·m⁻³ (BDD 0.5 k, j = 100 mA·cm⁻²).     

Prednisolone inhibits phagocytosis by polymorphonuclear leucocytes via steroid receptor mediated events

Prednisolone, at concentrations between 2·78 × 10⁻⁶ M (1 μg/ml) and 1·39 × 10⁻⁸ M (5 × 10⁻³ μg/ml) exerts an inhibitory effect on the phagocytosis of latex particles by normal human polymorphonuclear leucocytes in vitro as assessed by electron microscopical analysis. This inhibition appears to be receptor-mediated, as it is dependent upon RNA and protein synthesis and is glucocorticoid specific.     

Low Temperature Synthesis and Characterization of AlScMo3O12

Recent interest in low and negative thermal expansion materials has led to significant research on compounds that exhibit this property, much of which has targeted the A₂M₃O₁₂ family (A = trivalent cation, M = Mo, W). The expansion and phase transition behavior in this family can be tuned through the choice of the metals incorporated into the structure. An undesired phase transition to a monoclinic structure with large positive expansion can be suppressed in some solid solutions by substituting the A-site by a mixture of two cations. One such material, AlScMo₃O₁₂, was successfully synthesized using non-hydrolytic sol-gel chemistry. Depending on the reaction conditions, phase separation into Al₂Mo₃O₁₂ and Sc₂Mo₃O₁₂ or single-phase AlScMo₃O₁₂ could be obtained. Optimized conditions for the reproducible synthesis of stoichiometric, homogeneous AlScMo₃O₁₂ were established. High resolution synchrotron diffraction experiments were carried out to confirm whether samples were homogeneous and to estimate the Al:Sc ratio through Rietveld refinement and Vegard’s law. Single-phase samples were found to adopt the orthorhombic Sc₂W₃O₁₂ structure at 100 to 460 K. In contrast to all previously-reported A₂M₃O₁₂ compositions, AlScMo₃O₁₂ exhibited positive thermal expansion along all unit cell axes instead of contraction along one or two axes, with expansion coefficients (200–460 K) of α_a = 1.7 × 10⁻⁶ K⁻¹, α_b = 6.2 × 10⁻⁶ K⁻¹, α_c = 2.9 × 10⁻⁶ K⁻¹ and α_V = 10.8 × 10⁻⁶ K⁻¹, respectively.     

Global cost estimates of reducing carbon emissions through avoided deforestation

Tropical deforestation is estimated to cause about one-quarter of anthropogenic carbon emissions, loss of biodiversity, and other environmental services. United Nations Framework Convention for Climate Change talks are now considering mechanisms for avoiding deforestation (AD), but the economic potential of AD has yet to be addressed. We use three economic models of global land use and management to analyze the potential contribution of AD activities to reduced greenhouse gas emissions. AD activities are found to be a competitive, low-cost abatement option. A program providing a 10% reduction in deforestation from 2005 to 2030 could provide 0.3–0.6 Gt (1 Gt = 1 × 10⁵ g) CO₂·yr⁻¹ in emission reductions and would require $0.4 billion to $1.7 billion·yr⁻¹ for 30 years. A 50% reduction in deforestation from 2005 to 2030 could provide 1.5–2.7 Gt CO₂·yr⁻¹ in emission reductions and would require $17.2 billion to $28.0 billion·yr⁻¹. Finally, some caveats to the analysis that could increase costs of AD programs are described.     

Improved Electrical Characteristics of Gallium Oxide/P-Epi Silicon Carbide Static Induction Transistors with UV/Ozone Treatment Fabricated by RF Sputter

In this study, static induction transistors (SITs) with beta gallium oxide (β-Ga₂O₃) channels are grown on a p-epi silicon carbide (SiC) layer via radio frequency sputtering. The Ga₂O₃ films are subjected to UV/ozone treatment, which results in reduced oxygen vacancies in the X-ray photoelectron spectroscopy data, lower surface roughness (3.51 nm) and resistivity (319 Ω·cm), and higher mobility (4.01 cm²V⁻¹s⁻¹). The gate leakage current is as low as 1.0 × 10⁻¹¹ A at V_GS = 10 V by the depletion layer formed between n-Ga₂O₃ and p-epi SiC at the gate region with a PN heterojunction. The UV/O₃-treated SITs exhibit higher (approximately 1.64 × 10² times) drain current (V_DS = 12 V) and on/off ratio (4.32 × 10⁵) than non-treated control devices.     

Mayenite Synthesis from Hydroxide Precursors: Structure Formation and Active Sites on Its Surface

We studied the formation process of a mayenite structure from hydroxide precursors in different gas media. According to X-ray diffraction data, this method allows a well-crystallized mayenite (Ca₁₂Al₁₄O₃₃ or C12A7) phase to be obtained at low (500–900 °C) temperatures with an insignificant impurity of CaO. It was shown that the lattice parameters for C12A7 obtained in an inert atmosphere (Ar) were lower when compared with similar samples in the air. These results can be explained by the different levels of oxygen nonstoichiometry in the resulting phase. We noted that sintering and crystallization of mayenite proceeds at lower temperatures in Ar than in the air medium. We found the presence of donor and acceptor active sites on the surface of mayenite, which was detected by the spin probe method. The specific (per unit surface) concentration of such sites (2.5 × 10¹⁶ m⁻² and 1.5 × 10¹⁵ m⁻² for donor and acceptor sites, respectively) is comparable to that of γ-Al₂O₃, which is traditionally used as catalyst support. This allows it to be used in adsorption and catalytic technologies, taking into account its high specific surface area (~30–50 m²/g at a low synthesis temperature).     

Influence of Different Thermal Aging Conditions on Soot Combustion with Catalyst by Thermogravimetric Analysis

Diesel particulates are deposited in the diesel particulate filter and removed by the regeneration process. The Printex-U (PU) particles are simulated as the diesel soot to investigate the influence of thermal aging conditions on soot combustion performance with the addition of catalysts. The comprehensive combustion index S, combustion stability index R_w and peak temperature T_p are obtained to evaluate the combustion performance. Compared with the PU/Pt mixtures of different Pt contents (2 g/ft³, 3.5 g/ft³, and 5 g/ft³), the 10 g/ft³ Pt contents improve soot combustion with the outstanding oxygen absorption ability. When the weight ratio of PU/Pt mixture is 1:1, the promoted effect achieves the maximum degree. The S and R_w increase to 8.90 × 10⁻⁸ %²min⁻²°C⁻³ and 39.11 × 10⁵, respectively, compared with pure PU. After the thermal aging process, the PU/Pt mixture with a 350 °C aging temperature for 10 h promotes the soot combustion the best when compared to pure PU particles. It is not good as the PU/Pt mixture without aging, because the inner properties of soot and Pt/Al₂O₃ catalyst may have been changed. The S and R_w are 9.07 × 10⁻⁸ %²min⁻²°C⁻³ and 38.39 × 10⁵, respectively, which are close to the no aging mixture. This work plays a crucial role in understanding the mechanism of the comprehensive effect of soot and catalyst on soot combustion after the thermal aging process.     

Solid-State-Activated Sintering of ZnAl2O4 Ceramics Containing Cu3Nb2O8 with Superior Dielectric and Thermal Properties

Low-temperature co-fired ceramics (LTCCs) are dielectric materials that can be co-fired with Ag or Cu; however, conventional LTCC materials are mostly poorly thermally conductive, which is problematic and requires improvement. We focused on ZnAl₂O₄ (gahnite) as a base material. With its high thermal conductivity (~59 W·m⁻¹·K⁻¹ reported for 0.83ZnAl₂O₄–0.17TiO₂), ZnAl₂O₄ is potentially more thermally conductive than Al₂O₃ (alumina); however, it sinters densely at a moderate temperature (~1500 °C). The addition of only 4 wt.% of Cu₃Nb₂O₈ significantly lowered the sintering temperature of ZnAl₂O₄ to 910 °C, which is lower than the melting point of silver (961 °C). The sample fired at 960 °C for 384 h exhibited a relative permittivity (ε_r) of 9.2, a quality factor by resonant frequency (Q × f) value of 105,000 GHz, and a temperature coefficient of the resonant frequency (τ_f) of −56 ppm·K⁻¹. The sample exhibited a thermal conductivity of 10.1 W·m⁻¹·K⁻¹, which exceeds that of conventional LTCCs (~2–7 W·m⁻¹·K⁻¹); hence, it is a superior LTCC candidate. In addition, a mixed powder of the Cu₃Nb₂O₈ additive and ZnAl₂O₄ has a melting temperature that is not significantly different from that (~970 °C) of the pristine Cu₃Nb₂O₈ additive. The sample appears to densify in the solid state through a solid-state-activated sintering mechanism.